Differentiation of Actaea species by NMR metabolomics analysis

The ¹H NMR spectra of crude extracts from a total of 33 Actaea samples were acquired and analyzed for their species- and plant part-specific metabolomic characteristics by identifying fingerprint resonances via visual observation as well as a chemometric approach using principal component analysis (PCA). The main study subjects were the roots/rhizomes and aerial parts of three American species, Actaea racemosa (AR), Actaea podocarpa (AP) and Actaea cordifolia (AC). AP exhibited an already visually distinct chemical profile from those of the other two species. The species-characteristic resonances were identified as analytical chemotaxonomic markers. AR and AC exhibited visually similar ¹H NMR spectral profiles that required statistical analysis for differentiation. Several characteristic peaks and peak patterns were identified for each group of samples. Together with the three American Actaea species, the characteristics of the ¹H NMR spectra of Asian species are also discussed. A statistical analysis method using PCA was employed to provide the metabolomic profile for visually minor but analytically significant chemotaxonomic differences. PCA scores allowed differentiation between the three American Actaea species, as well as the ability to differentiate between the various plant parts (aboveground vs. roots/rhizomes).